Preserving the structural and functional integrity of biomolecules during isolation or purification from a biological sample is essential for various downstream applications. The downstream applications of purified biomolecules may include analyte detection, sensing, forensic, diagnostic or therapeutic applications, sequencing, amplification, and the like. The success of these downstream applications may depend on maintaining the integral structure and function of target biomolecules. Various factors, such as temperature, pressure, pH, chemical or enzymatic hydrolysis, or the presence of contaminants may cause degradation of biomolecules such as DNA, RNA or protein.
RNA is one of the most unstable biomolecules due to chemical self-hydrolysis and enzyme-mediated degradation. The extraction and stabilization of RNA derived from a biological sample is sensitive to a number of environmental factors including, but not limited to, the buffer used to extract or collect the RNA, solution pH, temperature, and particularly the ubiquitous presence of robust ribonucleases (RNases). RNA is typically stored under refrigeration (e.g. 4° C., −20° C., or −80° C.) in both purified and unpurified forms to prevent hydrolysis and enzymatic degradation and thus preserve the integrity of the RNA sample. The methods and articles for extraction and stabilization of RNA under ambient temperatures are desirable in order to avoid the costs and space requirements associated with refrigeration for maintaining the integrity of the RNA samples.
Current methodologies for stabilizing RNA under ambient temperature have focused on deactivating RNases in excess liquid solutions of, for example, detergents, chaotropic compounds, reducing agents, transitional metals, organic solvents, chelating agents, proteases, RNase peptide inhibitors, and anti-RNase antibodies. Additional efforts have focused on chemical modification of RNA to restrict trans-esterification and self-hydrolysis. Dry-state technologies claiming successful collection and preservation of RNA in dry formats typically require that RNA be “pre-purified” and concentrated from a sample prior to storage of the RNA. Other dry-state technologies for the preservation of RNA in dry formats require additional drying facilities (e.g. forced air flow, lyophilization, or heat treatment). These methods are therefore not conducive to direct RNA collection from a sample (e.g., a biological sample) without significant sample processing.
Accordingly, compositions and methods that enable dry-state RNA extraction and stabilization from a biological sample under ambient conditions within a single process-step are needed. Moreover, the ability to store a dried biological sample for a substantial period at ambient temperature and recover intact RNA thereafter for further analysis is highly desirable.